This protocol is designed to gather information about the natural progression of cancerous cells in the bronchial mucosa of the lung. In collaboration with Drs. William Krimsky and William McGuire of the Franklin Square Hospital Pulmonary and Oncology Divisions, we will receive normal and pathologic biopsy specimens obtained during screening bronchoscopies performed in patients at high risk for aerodigestive malignancies. The tissue will be obtained using a standard flexible bronchoscope that includes an Autofluoescence Brochoscopy (AFB) system with a camera unit. AFB is used in to detect malignant and premalignant lesions in the bronchial mucosa of the lung and has been shown to have a sensitivity rate of over 95%, often detecting lesions that are missed on sputum cytology (Lam et al, 1993;Pasic et al, 2003;Loewen et al, 2006). Biopsy specimens from premalignant and nearby healthy epithelium will be divided: half will be sent to Dr. Broussard of Franklin Square Department of Pathology, and the remaining half will be delivered to Dr. Kevin Becker at the National Institute on Aging. Gene expression profiling will be performed on normal and dysplastic specimens in an attempt to identify molecular pathways that are important for the development and progression of bronchial intra-epithelial neoplasia. This is a pilot study of paired biopsy specimens from 20 patients to determine the feasibility of obtaining reliable gene array data from very small tissue specimens, and to compare the data with pathologic classification of each specimen to determine if cellular heterogeneity within biopsies indicates the need to incorporate laser capture microdissection in future studies.